Device for obtaining centric registration in the construction of dentures



July 31, 1956 J. G. FEMINELLA DEVICE FOR OBTAINING CENTRIC REGISTRATION IN THE CONSTRUCTION OF DENTURES Filed April 29, 1955 4 INVENTOR. flrJo/m G. Fem/ mafia BY ATTORNEY United States Patent O i DEVICE FOR OBTAINING CENTRIC REGISTRA- TION IN THE CONSTRUCTION OF DENT URES John G. Femiuella, Great Neck, N. Y.

Application April 29,1955, Serial N 0. 504,839

7 Claims. (CI. 32-19) The comfort with which full dentures can be worn by a patient depends not only on how well the upper and the lower dentures fit on the patients dental arches, but also on the relative position of the upper and lower dentures to each other. Unless the upper and lower dentures are aligned in centric relation, it is impossible to set up the teeth in centric occlusion causing the patient to experience much discomfort and tiring of the muscles of mastication.

In the construction of the dentures the attainment of centric occlusion presents a problem. More specifically, the problem involves the transfer of the centric relation of the base trays and the bite rims to a dental articulator, a device which in the dental laboratory mechanically simulates the jaw movements of the patient with sufiicient accuracy to permit mounting of the individual teeth in such a way that the teeth of the dentures after insertion into the patients mouth produce the correct centric occlusion.

The present'invention provides a device which permits the accurate registration of the patients jaws in centric relation to be determined readily and accurately and permits the positional relationship to be fixed and transferred to the articulator for subsequent steps in the construction of the denture.

Briefly, the construction of the denture involves the following steps:

Preliminary impressions are first taken of the patients arches and preliminary plaster models are prepared from the impressions. Base trays are then formed or adapted on the preliminary model by placing sheets of thermoplastic material over the arches of the preliminary model, heating the material and pressing it into intimate contact with the model.

Wax rims are then put on the base trays. The base trays with the wax rims on them form units which are then used in the completion of the work which proceeds as follows:

The base trays are inserted into the patients mouth and the wax rims are trimmed to produce the proper height, lip line and other determinant factors. A final impression is then taken by means of the base trays to correct any minor inaccuracies which may be present in the preliminary impression.

The centric relation of the upper denture with regard to the lower denture is then determined. This is the relative position of the upper and lower jaws of the patient in which the heads of both condyles of the mandible are in their most retruded position in the Glenoid fossae. It involves both the antero-posterior as well as lateral position of the jaws. The determination of this relationsln'p involves difiiculties. It is rarely obtained by the first bite by the patient, since the patients jaws are generally not relaxed during the first bite. At this point the invennon is applied, as will be described in greater detail below.

After determination of the centric relation, the base trays with their wax rims are removed from the patients mouth and the further work is done in the dental laboratory. It involves the preparation of final models which 2,756,503 Patented July 31, 1956 are then mounted in a dental articulator for the subsequent mounting of the teeth. The teeth are selected for shape and color and are then set up in wax on the wax rims. At this stage the base trays with the provisionally mounted teeth are returned to the dentist for a final check of the proper fit in the patients mouth. Thereafter the denture is finished by the laboratory. The finishing work primarily involves replacement of the wax portions by denture material which then holds the teeth permanently.

The various objects, features and advantages of the invention will appear more fully from the detailed description which follows, accompanied by drawings showing, for the purpose of illustration, a preferred embodiment of the invention. The invention also resides in certain new and original features of construction and combination of elements hereinafter set forth and claimed.

Although the characteristic features of the invention which are believed to be novel will be particularly pointed out in the claims appended hereto, the invention itself, its objects and advantages and the manner in which it may be carried out may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part of it in which:

Fig. l is a perspective view of a device embodying the invention;

Fig. 2 is an exploded view of the device shown in Figure 1;

Fig. 3 is a perspective view of a dental articulator including models, base trays and bite rims on which two devices of Figure 1 are mounted; and

Fig. 4 is a perspective view illustrating a preferred mode of arresting the various movable parts of the inventive device in adjusted position by means of a dental explorer.

In the following description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be generic in their application. Corresponding reference numerals refer to corresponding parts in the several figures of the drawings.

The drawings accompanying, and forming part of, this specification, disclose certain specific details of the invention for the purpose of explanation of broader aspects of the invention, but it is understood that the details may be modified in various respects without departure from the principles of the invention and that the invention may be incorporated in other specific forms than the ones shown.

The alignment device embodying the present invention is preferably constructed of four individual parts, as shown in Figures 1 and 2. It comprises a base member 11 adapted to be fixedly embedded in the bite rim on a base tray. For this purpose the base member 11 is equipped with flanges 12 and 13. The base member comprises two end walls 14 and 15 between which a pair of parallel elevated tracks 16 and 17 extend.

A slide member 18 is longitudinally movable on the tracks 16 and 17 and is held thereon by depending lateral flanges 19 and 24) of which only one is visible in Figure 1. An elongated transversely disposed aperture 21 extends through the top of the slide member 18.

A cone 22 mounted on a stem 23 is seated on the slide member with the stem extending through the aperture. The stem comprises a threaded portion 24 fitting the internal threads 25 of a wheel-shaped nut 26. This nut is essentially a fiat disc, engaging with its top surface 27 the underside of the tracks 16 and 17 and protruding beyond the sides of the base member 11. The wheel nut may be knurled at its periphery 28 and is preferably provided with radially extending holes 29 distributed evenly about its periphery for insertion of a dental explorer 39 as shown in Figure 4, for loosening and tightening th nut on the threaded stem of the cone 22.

The portion of the stem between the cone 22 and the threaded portion 24 is provided with two flat surfaces 31 engaging the sides of the elongated aperture 21 to prevent the cone 22 from turning when the wheel nut 26 is beingtightened. V

The mounting of the cone permits longitudinal adjustment of the cone relatively to the base member 11 by reason of the slide member 18' andtransverse adjustment by reason of the elongated aperture 21.

The use of the device is best explained by reference to Figure 3. Figure 3 shows a dental articulator 32 comprising apivotal axis 33 by means of which an upper model 34 is hingedly movable relatively to a lower model 35 to simulate jaw movement.

The models 34 and 35 have base trays 36 and 37 of shellac on them on which base trays wax bite rims. 38 and 39' are fitted. The bite rims consist of wax.

In order to install the alignment devices, the lower base tray 37 is removed from the patients mouth and a piece of wax is cut out of the bite rim 39 in the second bicuspid and first molar regions on both sides. The alignment devices are then inserted in a position in which the upper surface of the slide member 18 is approximately flush with the top of the wax bite rim 39. The flanges 12 and 13 are anchored in place by means of sticky wax.

Thereafter the lower base tray with the alignment devices is inserted in the patients mouth.

The upper tray is then removed from the patients mouth and wax of the upper wax rim is heated in the region of the second bicuspid and first molar areas to make the wax soft enough to permit the cones 22 to make an impression. After heating of the aforementioned wax areas, the upper base tray is put in the patients mouth and the patient is then asked to close his jaws. In doing so the cones produce impressions 40 in the upper wax rim on both sides.

The upper base tray isthen removed and the wax rim is chilled to preserve the cone shaped impression. The upper base tray is then replaced in the patients mouth and the patient is asked to close his mouth repeatedly. If during these closings it is observed that the cones do not accurately fit into the cone shaped impression, due to the fact that the patient did not close his jaws in the correct centric relation at the time the cone shaped impressions were first produced, the wheels 26 are turned to loosen the cones. The cones will then automatically adjust themselves in a new position. The cones are then locked by turning the wheels with a dental explorer or by hand, thereby fixing the adjustment. The new position is then checked by repeated opening and closing of the month.

When the dentist is satisfied that the patient consistently closes in the same position in which the cones properly fit into the cone shaped depressions, the correct centric relation has been ascertained and is fixed for subsequent laboratory work. The base trays are then removed from the patients mouth and the laboratory has no diificulties in setting up the final models on the articulator in the correct centric relation, thereby assuring perfect centric occlusion of the dentures.

What is claimed is:

l. A device for obtaining centric registration in the construction of dentures by aligning the upper and lower jaws of a patient in centric relation, on which jaws base trays and bite rims are fitted to permit accurate transfer of that relation to a dental articulator, the device comprising, a base member adapted to be fixedly imbedded in the bite rim portion of one-half of the model, a slide member supported on said base member with freedom of longitudinal adjustment; a cone fitting a cone-shaped depression in the other half of the model, said cone being mounted on said slide member with freedom of lateral adjustment; and means mounted on said cone in engagement with said base member for arresting said cone in any position of longitudinal and lateral adjustment with respect to said base member.

2. A device for obtaining centric registration in the construction of dentures by aligning the upper and lower jaws of a patient in centric relation, on which jaws base trays and bite rims are fitted to permit accurate transfer of that relation to a dental articulator, the device comprising, a base member adapted to be fixedly imbedded in the bite rim portion of one-half of the model, a slide member supported on said base member with freedom of longitudinal adjustment; a cone fitting a cone-shaped depression in the other half of the model, said cone hava threaded stem and being mounted on said slide memher with freedom of lateral adjustment including means for preventing turning of said; cone relatively to said slide member; and a nut mounted on said threaded stem and in engagement with said base member for arresting said cone in any position of longitudinal and lateral adjustment with respect to said base member.

3. Adevice for obtaining centric registration in the construction of dentures by aligning the upper and lower jaws of a patient in centric relation, on which jaws base trays and bite rims are fitted to permit accurate transfer of that relation to. a dental articulator, the device comprising, a base member adapted to be fixedly imbedded in the bite rim portion of one-half of the model, said base member comprising a plate and a pair of longitudinally extending tracks thereon; a slide member supported on said tracks, said slide member having an elongated transversely extending aperture therein; a cone fitting a coneshaped depression in the other half of the model, said cone having a threaded stem extending through said I aperture of the slide member; and a nut on said threaded stern, said nut being larger in diameter than the space between said tracks to engage the underside of said tracks for arresting said cone and slide member in any position of longitudinal and lateral adjustment with respect to said base member.

4. A device as set forth in the preceding claim 3 in which the stem includes a flat-sided portion between the cone proper and the threaded portion, said fiat-sided portion engaging the sides of the elongated aperture in the slide member to prevent turning of said cone.

5. A device for obtaining centric registration in the construction of dentures by aligning the upper and lower jaws of a patient in centric relation, on which jaws base trays and bite rims are fitted to permit accurate transfer of that relation to a dental articulator, the device comprising, a base member adapted to be fixedly imbedded in the bite rim portion of one-half of the model, said base member comprising a plate and a pair of longitudinally extending elevated tracks thereon; a slide member supported on said tracks, said slide member having an elongated transversely extending aperture therein; a cone fitting a cone-shaped depression in theother half of the model, said cone comprising a cone-shaped head portion above said slide member, a flat-sided intermediate stem portion engaging the sides of the elongated aperture in the slide member to prevent turning, and a threaded stem portion depending between said tracks; and a nut on said threaded stern portion, the nut being larger in diameter than the space between said tracks to engage the underside of said tracks, said nut having substantially radially extending holes in its periphery for insertion of a dental explorer tool as a wrench for tightening the nut in the patients mouth.

6. A device for obtaining centric registration in the construction of dentures by aligning the upper and lower jaws of a patient in centric relation, on which jaws base trays and bite rims are fitted to permit accurate transfer of that relation tov a dental articulator, the device comprising, a base member adapted. to be fixedly imbedded in the bite rim portion of one-half of the model; a dowel member comprising a cone fitting a cone-shaped depression in the other half of the model, and a stem on said cone, said dowel member being mounted on said base member With freedom of longitudinal and lateral ad-.

justment; and means engaging said stem and said base member for frictionally arresting said dowel member in any position of longitudinal and lateral adjustment with respect to said base member.

7. A device for obtaining centric registration in the construction of dentures by aligning the upper and lower jaws of a patient in centric relation, on which jaws base trays and bite rims are fitted to permit accurate transfer of that relation to a dental articulator, the device comprising, a base member adapted to be fixedly imbedded in the bite rim of one-half of the model, the base member comprising, two substantially parallel end walls, a base plate supporting said end walls, the base plate extending beyond the end walls to form exterior flanges, and a pair of parallel elevated tracks extending between the end walls, there being a space between said base plate and said tracks; a slide member supported on said tracks, said slide member having an elongated transversely extending aperture therein; a cone fitting a cone-shaped depression in the other half of the model, said cone comprising a cone-shaped head portion above said slide member, a flatsided intermediate stem portion engaging the sides of the elongated aperture in the slide member to prevent turning, and a threaded stem portion depending between said tracks; and a nut on said threaded stem portion, the nut being larger in diameter than the space between said tracks and located between said base plate and said elevated tracks to engage the underside of said tracks upon being tightened, said nut having substantially radially extending holes in its periphery for insertion of a dental explorer tool as a wrench for tightening the nut in the patients mouth thereby arresting the cone in centrically adjusted position.

No references cited 

